The present invention relates to a plate inserting apparatus in a rotary printing press and, more particularly, to a positioning apparatus for temporarily positioning a plate in inserting it into a plate fixing unit of a plate cylinder.
In a plate inserting apparatus of this type, generally, in inserting a plate into a plate fixing unit using a plate inserting member while positioning the plate with reference to a reference pin, the plate is temporarily positioned using another reference pin on the plate inserting member. This positioning is canceled immediately before the plate is inserted into the plate fixing unit. A conventional positioning apparatus is disclosed in Japanese Patent Laid-Open No. 6-134973.
The plate inserting apparatus disclosed in this reference has a plate cylinder which has a leading edge plate clamp with a reference pin, a loader having a plate setting unit swingably supported in directions to come close to and separate from the outer surface of the plate cylinder to set a new plate, and a reference pin disposed retreatable with respect to the distal end of the loader. In this arrangement, before the distal end of the loader is opposed to the plate clamp of the plate cylinder upon swinging the loader to insert the plate into the plate clamp, the reference pin of the loader is retreated to cancel positioning between the reference pin and the new plate.
In the conventional plate inserting apparatus in a rotary printing press described above, the reference pin itself is retreated in inserting the plate into the plate clamp. A dedicated driving unit for reciprocating the reference pin is required in the loader. This increases the number of components and complicates the structure.
It is an object of the present invention to provide a simple plate inserting apparatus in a rotary printing press by reducing the number of components.
In order to achieve the above object of the present invention, there is provided a plate inserting apparatus in a rotary printing press for inserting a plate into a plate fixing unit of a plate cylinder, comprising a plate holder moving between a first position where the plate holder holds the plate and a second position where the held plate is inserted into the plate fixing unit of the plate cylinder, a cover for selectively opening and closing a plate insertion side of the plate cylinder, and a first reference pin fixed to the cover to position the plate before held by the plate holder when the plate holder is located at the first position.